1. Field of the Invention
The invention relates to a process for the manufacture of large crystalled 1,3,5-triaminotrinitrobenzene (TATB) by amination, e.g., by means of NH.sub.3, from 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) at an elevated temperature.
2. Description of Prior Art
Recently, triaminonitrobenzene has been in particular demand as a special explosive. The reason for this is its extraordinary resistance to shock (insensitivity), its high density and its accelerated detonation with respect to classical TNT explosive. More widespread acceptance of this particular explosive has been hindered by the enormously elevated manufacturing costs involved which are many times greater than with conventional explosives.
In the manufacture of TATB one generally starts with trichlorotrinitrobenzene (TCTNB) since this starting material, contrary, for example, to tribromotrinitrobenzene is relatively inexpensive. In a known process (Rev. trav. chim. 56 [1937] 1175) the amination of TCTNB is performed by reaction with aqueous ammonia solution in a low boiling solvent such as ethanol or toluene. After a relatively long reaction time a very fine product having an average crystal size of 10 microns is formed. However, it is difficult to work with such a fine product.
When the explosive is to be poured or pressed as is commonly required, it is preferable to have a size distribution of between about 40 to 250 microns. With such a distribution it is possible to achieve the desired viscosity in the pour mixture as well as to reduce the amount of additives which are necessary for pouring or pressing thereby achieving an elevated explosive density.
So as to achieve these objectives, U.S. Pat. No. 4,032,377, the disclosure of which is hereby incorporated by reference, discloses a technique in which the reaction described above is performed at 150.degree. C. However, according to this technique the pressure is adjusted at this temperature such that the reaction occurs at a considerable excess pressure (35-40 psig). In such a technique large crystalled materials are obtained which are more favorable for subsequent processing. However, the advantages of large crystal size achieved according to this technique are obtained at the expense of increased pressure which requires correspondingly larger and more costly apparatus. This further increases the already elevated costs of manufacture.